No abstract

A PGeP pincer-type germylene, Ge(NCHPBu)CH, which contains two phosphane groups hanging from the N atoms of an N-heterocyclic germylene fragment, has been isolated for the first time. This compound has already furnished a rich transition metal derivative chemistry (Co, Rh, and Pd) that includes complexes containing bridging P,Ge,P-, chelating P,Ge- and pincer P,Ge,P-ligands.

The PGeP pincer-type germylene Ge(NCH PtBu )C H (1) has been used to prepare a family of group 10 metal complexes, namely, [MCl{κ P,Ge,P-GeCl(NCH PtBu ) C H }] (M=Ni (2 ), Pd (2 ), Pt (2 )), featuring a chloridogermyl PGeP pincer ligand and a Cl-Ge-M-Cl bond sequence. Their reactivity is not initially centered on the metal atom but on their Ge atom. Complexes 2 and 2 easily led to the hydrolyzed products [Ni Cl {μ-(κ P,Ge,P-Ge(NCH PtBu ) C H ) O}], which features a Cl-Ni-Ge-O-Ge-Ni-Cl bond sequence, and [PdCl{κ P,Ge,P-Ge(OH)(NCH PtBu ) C H }], which contains a hydroxidogermyl PGeP pincer ligand (2 is reluctant to undergo hydrolysis). Simple chloride exchange reactions led to the methoxidogermyl, methylgermyl, and phenylgermyl derivatives [MCl{κ P,Ge,P-GeR(NCH PtBu ) C H }] (M=Pd, Pt; R=OMe, Me, Ph). Whereas the palladium complexes [PdCl{κ P,Ge,P-GeR(NCH PtBu ) C H }] (R=Me, Ph) reacted with more MeLi or PhLi to give palladium black and GeR (NCH PtBu ) C H (R=Me, Ph), similar reactions with the analogous platinum complexes afforded the transmetalation derivatives [PtR{κ P,Ge,P-GeR(NCH PtBu ) C H }] (R=Me, Ph). The short length of the CH PtBu arms of the PGeP pincer ligands forces the metal atoms of all these complexes to be in a very distorted square-planar ligand environment. The reactivity results have been rationalized with theoretical calculations.